Forge Intake Pressure Compensation Valve

VW/Audi Performance Parts: Forge Intake Pressure Compensation Valve (FMIPCV)

Product Features & Benefits

Dump valves, Blow-off valves, call them what you will, but hopefully, we’re all reasonably familiar with the concept these components are a safe way of allowing excess boost to escape harmlessly when off-throttle, and holding the boost system tightly in check when mashing it into the carpet. Excess boost vents either to the atmosphere, with its familiar metallic sneeze, or for those that prefer their journey to sound a little more subtle, back to the low pressure side of the turbo circuit, depending on the type of valve you run. On cars with low or factory boost pressures, the spring or diaphragm inside these valves only has to be a fairly weak affair. This allows the valve to move quickly and freely, but with the downside that the valve is useless on a tuned or high-boost car. That lack of resistance simply won’t be able to keep the valve gas-tight as the boost pressure increases.

If only there was a way to make the dump valves spring operation completely independent of the spring pressure inside. A way to allow its function to work perfectly at any boost level. Clearly concerned by this very same problem, Forge’s technicians beavered away to find a solution. What they came up with is called the Intake Pressure Compensation Valve (or IPCV for short). What makes the IPCV valve ingenious is that it re-routes the various high and low pressure feeds through a clever internal piston system (see diagram). When the throttle is opened and the car is accelerating, boost pressure generated by the turbocharger will ensure that whichever dump valve or recirculation valve you have fitted will be kept sealed. As no boost is now being lost through the intercooler (which can usually be anywhere between 1-3 psi of boost drop) the pressure acting on top of the piston of your dump valve is precisely equal to that underneath it. The result? Only a relatively weak spring is required to keep it operating, which means response times can be kept quick and throttle response is immediate.

Additional Details

Fitment:

• Audi A3 1.8T
• Audi A3 1.8 TFSI
• Audi S3 1.8T 8L
• Audi TT Mk1 1998-2006
• Porsche 996/911 Turbo
• Seat Ibiza Mk4
• Seat Leon Cupra R 1.8T
• Skoda Octavia 1.8T
• VW Golf Mk4 1.8T
• VW Passat 1.8T
• VW Polo 1.8T

In The Box:

• 1 x FMIPCV Valve
• 1 x 2000mm Length of 5mm Vacuum Hose
• 1 x Flat Bracket
• 1 x Bent Bracket
• 1 x 5mm T Piece
• 1 x 6mm T Piece
• 1 x 6mm Joiner
• 1 x M6 Penny Washer
• 1 x M8 Penny Washer
• 3 x Alternative Vacuum Ports
• 2 x M4 x 6 Socket Cap Screws
• 1 x Instructions
• 1 x Forge Sticker

As dump valve springs usually have to compensate for the pressure drop across the intercooler, and this problem is now no longer an issue, the dump valve can now be run with a very weak spring. In fact, during testing, Forge Motorsport has actually been able to make this system work with no spring in the dump valve at all!

When the throttle is snapped shut either to change gear, or on over-run, the vacuum created by the engine opens up the dump valve and allows the air to either recirculate back around the turbo (in the case of a recirculation valve) or straight back out to the atmosphere. Put simply, what these means, is that even on a fire-breathing 1200 bhp GT-R, the dump valves now only require a very weak spring to operate perfectly with no boost loss, allowing them to open more responsively on partial throttle, improving performance in every gear, and at whatever revs you care to use. Best of all, this principle works as well on a bone-stock Subaru WRX as it does on a Drag-spec Evo. Boost levels simply don’t affect this part of the equation any more.